Leg wear for sleep

ABSTRACT

The leg wear for sleep according to an aspect of the present invention is leg wear adapted to be worn during sleep and has a double-layered structure in which an inside member and an outside member that do not constrict the foot of a wearer are layered. The inside member has a napped surface, and the outside member has a higher drape and a smoother surface than the inside member.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No. 61/213,984 filed on Aug. 5, 2009 by the same Applicant, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to leg wear to be worn during sleep.

2. Related Background Art

Sleep is considered to play an important role in human life, such as in recovery from fatigue, the activation of immune cells and control of the autonomic nerves. For this reason, the inhibition of sleep has a variety of adverse effects on the human body; conversely, sound sleep is known to contribute significantly to one's health. Many women suffer from poor circulation, and it is not uncommon for cold feet in particular to be an impediment to sleep. Some people sleep with socks on to minimize the problem of cold feet, but constriction by the socks leads to discomfort or may be counterproductive by interfering with blood circulation. When loose socks are worn, they tend to slip off in bed.

Japanese Patent Application Laid-open No. 2005-68588 addresses such concerns by disclosing a sock which has a construction that does not constrict the foot and helps prevent the sock from slipping off the foot. Specifically, by sewing together a plurality of fabric pieces cut to the three-dimensional shape of the foot and in particular by placing the seams on the heel, this prior art claims to discourage the sock from slipping off without constricting the foot.

SUMMARY OF THE INVENTION

However, because socks are articles of apparel whose basic purpose is to protect and keep the skin warm during daytime activities, and are not intended for helping one to sleep comfortably, even when socks of a type worn daily or socks in which only the insulating properties have been increased are worn to prevent cold feet, achieving a restful sleep is often impossible. It is commonly said that, in order to sleep soundly, the deep body temperature must be lowered in order to allow the brain to rest and to prevent the consumption of energy. Yet, such prior-art socks sometimes interfere with a lowering of the deep body temperature.

It is therefore an object of the present invention to provide leg wear for sleep capable of warming the feet and also helping lower the deep body temperature during sleep.

It is known that the human body efficiently lowers the deep body temperature by dilating the blood vessels known as the arteriovenous anastomoses (AVA). The arteriovenous anastomoses play the role of bypasses that shorten arterioles and venules. Dilating these vessels during sleep increases the amount of arterial blood flow and raises the skin temperature; heat released from the skin surface lowers the deep body temperature. Through repeated and extensive investigations, the inventors have found that it is possible to promote dilation of the arteriovenous anastomoses. In order to dilate the arteriovenous anastomoses of the feet, it was important to raise the average skin temperature of the lower leg that accounts for about 20% of the body surface and also to be in a relaxed state, that is, to increase the activity of the parasympathetic nerves. Eliminating stress such as a sense of tightness and irritation of the skin, and imparting a sense of ease and a comfortable feel against the skin are regarded as effective for increasing parasympathetic nerve activity.

Accordingly, the leg wear for sleep of the present invention is leg wear adapted to be worn during sleep and has a double-layered structure in which an inside member and an outside member that do not constrict the foot of a wearer are layered. The inside member has a napped surface, and the outside member has a higher drape and a smoother surface than the inside member.

When this leg wear for sleep is worn, because the surface of the inside member is napped, the foot can be warmed without the wearer sensing any coldness, in addition to which a comfortable feel against the skin can be achieved.

Moreover, because this member does not constrict the wearer's foot, the leg wear is not uncomfortable even when worn to bed. In addition, the outside member has a high drape and a smooth surface, and so is supple and soft, enabling a smooth feel against the skin to be obtained. As a result, when this leg wear for sleep is picked up and put on, that is, from prior to sleep, the hands sense the comfortable feel against the skin, thereby enabling parasympathetic nerve activity to be increased.

Because the inside member raises the average skin temperature and the outside member increases the parasympathetic nerve activity prior to sleep, dilation of the arteriovenous anastomoses is promoted, which can help lower the deep body temperature. As a result, sound sleep is achievable.

Preferably, the outside member is composed of microfibers up to 0.7 denier in size. This enables the outside member to have a high drape and a smooth surface. That is, an outside member can be obtained which is supple and soft, and which has a smooth feel. As a result, when this leg wear for sleep is picked up and put on, that is, from prior to sleep, the hands sense the comfortable feel against the skin, thereby enabling parasympathetic nerve activity to be increased.

The nap of the inside member is preferably composed of microfibers having a length of from 10 mm to 70 mm and a density of from about 200 g/m² to about 500 g/m². This reduces the sensation of coldness when worn, enabling warmth to be achieved. Also, a layer of air can be formed between the base fabric of the inside member and the skin of the wearer, enabling insulating properties to be increased. In addition, tightness is reduced, making it possible to achieve a comfortable feel.

Preferably, the leg wear for sleep is further composed of a fastening member to prevent the leg wear for sleep from slipping off the foot of the wearer, the fastening member having non-stretch properties. In this way, when the wearer moves or changes position during sleep, the leg wear will not slip down or come off the foot, enabling the desirable effects to continue. Also, the non-stretch properties of such a fastening member are desirable in that the degree of tightening can be adjusted by the wearer at, for example, the position where the leg wear is tied.

It is preferable for the leg wear for sleep to have a sole having a nonslip function. With the nonslip sole, when the leg wear is worn other than while sleeping, the wearer is able to walk indoors with the leg wear on in relatively safety.

The leg wear for sleep according to the present invention warms the foot and also increases parasympathetic nerve activity, thereby enabling the arteriovenous anastomoses to be dilated, and thus helping lower the deep body temperature during sleep. As a result, the wearer is able to sleep soundly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing leg wear for sleep according to an embodiment of the present invention;

FIG. 2 is an enlarged side view of the toe portion of the leg wear for sleep in FIG. 1;

FIG. 3 is a view from the bottom side showing the sole portion of the leg wear for sleep in FIG. 1;

FIG. 4 is a partial cross-sectional view showing a portion of a cross-section taken along line IV-IV in FIG. 1;

FIG. 5 is a graph showing average cycles in the deep body temperature (rectal temperature) of humans;

FIG. 6 is a schematic view of an arteriovenous anastomosis;

FIG. 7 is a diagram showing the results of thermal sensation of touch tests;

FIG. 8 is a diagram showing results of tests on the skin temperature and amount of blood flow in a wearer during sleep (Subject A);

FIG. 9 is a diagram showing the results of tests on the skin temperature and amount of blood flow in a wearer during sleep (Subject B); and

FIG. 10 is a diagram showing the results of tests on the skin temperature and amount of blood flow in a wearer during sleep (Subject C).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the invention are described in detail below while referring to the accompanying diagrams. In the respective diagrams, like numbers refer to like or corresponding elements.

As noted above, FIG. 1 is a perspective view showing leg wear for sleep according to an embodiment of the present invention, FIG. 2 is an enlarged side view of the toe portion of the leg wear in FIG. 1, FIG. 3 is a view from the bottom side of the sole portion of the leg wear in FIG. 1, and FIG. 4 is a partial cross-sectional view showing a portion of a cross-section taken along line IV-IV in FIG. 1. Referring to these diagrams, this leg wear for sleep, which is adapted to be worn during sleep in order to prevent cold feet and enable the wearer to sleep soundly, has a double-layered structure in which an outside member 10 and an inside member 20 are layered.

The outside member 10 is in turn composed of a shin-instep member 11 which covers the shin and instep portions of the leg, a calf member 12 which covers the calf portion of the leg, and a sole member 13 which covers the bottom of the foot. The shin-instep member 11 and calf member 12 are sewn together at a seam 14 on the side of the leg, and the shin-instep member 11 and sole member 13 are sewn together at a seam 15 on the side of the foot. The calf member 12 and the sole member 13 are sewn together at a seam 16 on the ankle. Although the outside member 10 may be knit as leg wear by tubular knitting on a hosiery knitting machine, this is undesirable because it gives rise to the undesirable sense of tightness, or constriction, described above.

The inside member 20 is similarly composed of a shin-instep member 21 which covers the shin and instep portions of the leg, a calf member 22 which covers the calf portion of the leg, and a sole member 23 which covers the bottom of the foot. The shin-instep member 21 and calf member 22 are sewn together at a seam 24 on the side of the leg, and the shin-instep member 21 and sole member 23 are sewn together at a seam 25 on the side of the foot. The calf member 22 and the sole member 23 are sewn together at a seam 26 on the ankle.

The inside member 20 has a turned-back portion 27 which is turned back at a top opening where the foot is inserted, the turned-back portion 27 and the outside member 10 being sewn together at a seam 17.

It is preferable to use, for example, zigzag stitches which have a good feel against the skin as the method for sewing members together at the seams 14 to 16, 17 and 24 to 26. Moreover, to facilitate such sewing, it is advantageous to adhesively bond together the outside member 10 and the inside member 20 over part or all of the surfaces thereof.

The outside member 10 and inside member 20 are materials having low-stretch properties so as not to constrict the wearer's foot, and are cut and sewn in such a way as to impart an appropriate sense of ease and comfort when the leg wear is worn.

In this embodiment, referring to FIG. 2, the sole member 13 is three-dimensionally formed by a shining technique in such a way that the sole 30 of the leg wear extends out to the toe 32 thereof. In this way, the seam 15 is positioned above the surface of the sole 30 which comes into contact with the ground, helping to keep the wearer from tripping when walking.

Also, as shown in FIG. 3, the sole 30 is provided with one or more nonslip element 34. In this embodiment, the nonslip element 34 is a rubber member, a plurality of which are provided on the sole 30. When the leg wear is worn other than while sleeping, such nonslip elements 34 enable the wearer to walk indoors with the leg wear on in relatively safety.

Next, the outside member 10 and the inside member 20 are described in detail.

Referring to FIG. 4, the shin-instep member 21, calf member 22 and sole member 23 of the inside member 20 are composed of a base fabric 28 and a nap 29 which rises from the base fabric 28. A boa-style fabric with a construction in which fiber bundles emerge from required point locations in a base fabric, as in the case of a blanket, is used as this inside member 20. Such an arrangement gives both the surface of the inside member 20 on the side with which the foot comes into contact and the surface on the turned-back portion 27 a napped state.

The nap 29 on the inside member 20 is composed of polyester microfibers having a length of from about 10 mm to about 70 mm, and has a nap density of from about 200 g/m² to about 500 g/m². It is possible to use some other material instead of microfibers. In the case synthetic fibers, although the use of acrylic or nylon is also conceivable, polyester is particularly useful on account of its warmth to the touch. In the case of natural fibers, animal fibers such as wool have a large denier and are prickly when worn, which is undesirable. Vegetable fibers such as cotton also leave something to be desired in that they lack quick-drying properties. It is even more preferable for the nap 29 on the inside member 20 to have a length of from about 15 mm to about 30 mm, and a density of from about 300 g/m² to about 400 g/m²

When the nap 29 has a length of at least about 10 mm and a density of at least about 200 g/m², the sense of coldness on wearing the leg wear is reduced, enabling warmth to be achieved. Moreover, an air layer can be formed between the base fabric 28 and the skin of the wearer, enabling the insulating properties to be increased. In addition, by using microfibers, the feel against the skin can be improved. Nap 29 with a length in excess of about 70 mm, and preferably in excess of about 30 mm, may cause the feet to feel uncomfortable, as if there is too much play, when the leg wear is worn. At a nap density in excess of about 500 g/m², and preferably in excess of about 400 g/m², the feel against the skin may become harder.

The outside member 10 is knit from exceedingly fine acrylic microfibers having a size of up to about 0.7 denier. The use of exceedingly fine acrylic microfibers having a size of up to about 0.4 denier is more preferred. In this way, the outside member 10 has a higher drape and softness than the inside member 20, and also has a smoother surface than the inside member 20. As a result, a supple, soft and smooth feel against the skin can be achieved. As with the inside member 20, it is possible to use some other material in the outside member 10, although there is a possibility that the same problems will arise.

It is preferable for the surface or fibers of this outside member 10 to have an anti-pilling ability so as not to compromise the appearance.

A fastening member 40 for preventing the leg wear from slipping or coming off the wearer's foot is provided at the top opening where the foot is inserted. The fastening member 40 is preferably a non-stretch material which allows the wearer to adjust the degree of tightness himself or herself. In this embodiment, the fastening member 40 is a cord with pompoms at the ends, and is provided at the turned-back portion 27 of the inside member 20.

FIG. 5 shows average cycles in the deep body temperature (rectal temperature) of humans. In FIG. 5, using the abscissa to represent time (hours) and the ordinate to represent the deep body temperature (° C.), the change in the deep body temperature from 12 o'clock noon until the time one rises the next morning is traced with a solid line for two consecutive days. As is apparent from FIG. 5, the deep body temperature starts to drop around the time one falls asleep and reaches its lowest level around 4 AM, then begins to rise before one awakes. The drop in the deep body temperature at the time of sleep is generally thought to occur in order to give the brain a rest and prevent the consumption of energy. Interfering with this impedes sound sleep.

Deep sleep is easily achieved for about 3 hours after initially falling asleep, subsequent to which sleep tends to become shallower. The deep body temperature up until about 3 hours after falling asleep, i.e., during the deep sleep associated with sound sleep, is regarded as important for sound sleep.

It is known that the human body can efficiently lower the deep body temperature by dilating the blood vessels known as the arteriovenous anastomoses (AVA). FIG. 6 is a schematic diagram of an arteriovenous anastomosis. The arrows in FIG. 6 indicate blood flow. Arteriovenous anastomoses are located only in the hands, feet and face, and play the role of a bypass, located just before the capillaries, between an artery and a vein. The arteriovenous anastomoses have a diameter which is about ten times the diameter of capillaries, and the blood flow through an arteriovenous anastomosis is reportedly about 10,000 times that through a capillary. Dilating these arteriovenous anastomoses causes the amount of arterial blood flow to increase and the skin temperature to rise. The ensuing release of heat results in a decrease in the deep body temperature.

The conditions for dilating these arteriovenous anastomoses are, first, to elevate the average skin temperature, and second, to be in a relaxed state; that is, to increase the parasympathetic nerve activity. Moreover, elevation of the average skin temperature is thought to be linked to dilation of the arteriovenous anastomoses via heat input to the brain.

When the leg wear for sleep 1 according to the present embodiment is worn, because the inner surface of the inside member 20 is napped, the foot can be warmed without the wearer sensing any coldness. In addition, unnecessary tightening is avoided, making it possible to achieve a comfortable feel on contact and also a sound sleep.

Moreover, because the inside and outside members 10 and 20 are low-stretch members which do not constrict the foot, there is no discomfort even when the leg wear is worn to bed. Also, the high drape and softness and the smooth surface of the outside member 10 enable a feel against the skin that is supple, soft and smooth to be achieved. As a result, by experiencing the comfortable sensation of this leg wear for sleep against the hand when it is picked up and put on, that is, from prior to sleep, the parasympathetic nerve activity can be increased.

In this way, owing to the elevation in the average skin temperature by the inside member 20 and the increase in parasympathetic nerve activity by the outside member 10, dilation of the arteriovenous anastomoses is promoted sooner after going to bed, which can help lower the deep body temperature. Consequently, the wearer easily enters a deep state of sleep about 3 hours after going to bed, and is thus able to enjoy a sound sleep.

The present invention is not limited to the embodiment described herein, and may be practiced using any variations and modifications thereof encompassed by the inventive ideas as set forth in the appended claims.

In the foregoing embodiment, leg wear for sleep having a length which covers the shin and the calf has been described. However, the inventive leg wear for sleep is not limited to this length. For example, depending on the preferences of the wearer, the leg wear may be of a shorter type which only extends to the vicinity of the ankle, or may be a longer type which extends to above the knee.

Also, the fastening member is exemplified in the present embodiment by a cord with pompoms at the ends, but is not limited to this form. For example, fastening members in any of various forms, such as hook-and-loop fasteners or belts, may be suitably employed, provided that they have non-stretch properties and do not constrict the foot.

Examples

Leg wear for sleep 1 according to the embodiment of the present invention shown in FIG. 1 was fabricated as a working example, and subjected to the following tests. In the above-described leg wear for sleep 1 of this example, the nap on the inside member 20 was composed of microfibers having a length of about 15 mm and had a nap density of about 300 g/m². Exceedingly fine microfibers having a size of about 0.4 denier were used in the outside member 10.

Thermal Sensation of Touch

Comparative tests between the working example and comparative examples were carried out on the thermal sensation of touch in order to ascertain the degree to which warmth is sensed the moment that the leg wear is put on.

The comparative examples, used here for the sake of comparison with the working example, were commercial products of the applicant which are capable of being used as socks. Comparative Example 1 was a sock having a single-layer construction that was knit on an ordinary knitting machine for hosiery using cotton and acrylic-containing synthetic fibers. Comparative Example 2 was a sock having a single-layer construction that was similarly knit on an ordinary knitting machine for hosiery using cashmere-containing yarn.

The results are shown in FIG. 7. The ordinate represents the thermal sensation of touch (w/cm²), and the magnitude of the values for each sample is indicated by the height of a bar graph. A smaller thermal sensation of touch value in FIG. 7 signifies that a sensation of warmth rather than coldness was experienced at the time of touch. From FIG. 7, it is apparent that, in contrast with Comparative Examples 1 and 2, the sensation at the time of touch in this working example was one of warmth, not of cold. This appears to be attributable to the surface of the inside member 20 being napped and to both the use of polyester microfibers having a length of about 15 mm as the nap and the nap density of about 300 g/m²

Skin Temperature and Blood Flow in Wearer During Sleep

The skin temperature and blood flow of the wearer during sleep were measured when three subjects wore leg wear from the above examples. These are comparative tests between periods when the subjects wore leg wear from the working example of the invention or leg wear from Comparative Example 1, or when the subjects' feet were bare.

Subject A was a 25-year-old female with a moderate degree of poor circulation, Subject B was a 24-year-old female with a moderate degree of poor circulation, and Subject C was a 30-year-old male with a low degree of poor circulation.

The test results for Subjects A to C are shown in FIGS. 8 to 10, respectively. FIGS. 8 to 10 measure the changes in skin temperature and blood flow during sleep, with the abscissa representing time (with 0 minutes being when the subject went to bed), the left ordinate representing skin temperature, and the right ordinate representing blood flow. The skin temperature and blood flow were both measured at the great toes. In FIGS. 8 to 10, curves 51 a and 51 b respectively represent the skin temperature and blood flow when the leg wear of the working example of the present invention was worn, curves 52 a and 52 b respectively represent the skin temperature and blood flow when the leg wear of Comparative Example 1 was worn, and curves 53 a and 53 b respectively represent the skin temperature and blood flow when the subject's feet were bare.

From FIGS. 8 to 10, it can be seen that in the working example, compared with Comparative Example 1 and when the subject's feet are bare, for a period of about 90 minutes from the time the subject goes to bed, blood flow is increased and the skin temperature is elevated relatively rapidly; i.e., heat release is induced. It is apparent from these results that, compared with Comparative Example 1 and when the subject's feed were bare, the working example promotes dilation of the arteriovenous anastomoses and is able to more effectively assist in lowering the deep body temperature. One major factor underlying this is the rise in the average skin temperature on account of the inside member 20. Another major factor is has to do with the fact that, owing to the high drape and smooth surface of the outside member 10, the leg wear of the working example, compared with Comparative Example 1 and bare feet, is supple and soft and is thus able to achieve a smooth feel against the skin. As a result, until it is picked up and put on (that is, prior to sleep), the leg wear of the working example imparts a comfortable feel to the hands, enabling the parasympathetic nerve activity to be more effectively increased. In addition, the increase in blood flow appears to indicate that coldness of the feet has been reduced.

Impressions by Monitors

Evaluations were carried out in which 129 monitors tried on the leg wear of the working example during sleep, and were asked for their impressions. Here is a sampling of their responses.

-   -   My feet were wrapped in soft warmth, allowing me to sleep better         than before.     -   I was able to sleep with the leg wear on until morning without         any sense of unease.     -   It was warm and left me feeling relaxed.     -   In any case, it felt good against the skin and my feet did not         get cold.     -   When I put the leg wear on, it quickly warmed my cold feet.     -   The sensation of being wrapped in a blanket down to my toes felt         nice.     -   My feet really did not get cold at all.     -   Once my feet get cold, I can't fall asleep until they warm up         again. But this made my feet warm up right away, letting me         sleep well.     -   Once I run into socks like these, I will never be able to do         without.

These results serve to demonstrate that the leg wear for sleep 1 according to the present invention can genuinely relieve the wearer of cold feet and make sound sleep possible. 

1. Leg wear for sleep adapted to be worn during sleep, comprising a double-layered structure in which an inside member and an outside member that do not constrict the foot of a wearer are layered, wherein the inside member has a napped surface, and the outside member has a higher drape and a smoother surface than the inside member.
 2. The leg wear for sleep according to claim 1, wherein the outside member is composed of microfibers up to 0.7 denier in size.
 3. The leg wear for sleep according to claim 1, wherein the nap of the inside member is composed of microfibers having a length of from 10 mm to 70 mm and has a density of from 200 g/m² to 500 g/m².
 4. The leg wear for sleep according to claim 1, further comprising a fastening member to prevent the leg wear for sleep from slipping off the foot of the wearer, the fastening member having non-stretch properties.
 5. The leg wear for sleep according to claim 1, which has a sole having a nonslip function. 